21 September 2018
Colin Smith | Hawke's Bay Today, Hawke's Bay
When an invitation arrived to sample Mazda's SkyActiv Vehicle Dynamics in the winter conditions at the Southern Hemisphere Proving Ground near Queenstown I jumped to the obvious assumption - it would be a day to showcase the all-wheel-drive skills of the CX range.
I was half correct. But the Mazda I hadn't expected to steer on the snow turned out to be the star attraction of a winter driving experience.
Sliding in the white stuff in an MX-5 RF - powered roof open of course because it wasn't actually snowing at the time - was a chilly blast I hadn't seen coming.
Apply enough throttle to break traction and settling the roadster into a oversteer balance made slow speed but exciting drift circles in the snow until I spun to the inside or understeered onto an arc even wider than my smile.
With test venues to explore the traction limits well clear of snow banks and rocky outcrops it was the MX-5 RF with its ideal weight distribution, rear-wheel-drive poise and quick steering that delivered the low grip and high grin experience.
The other interesting rear-drive experience turned out to be sheet ice circles at idle speed in a BT-50 ute that had been left in rear drive with all electronics switched off - an exercise in patience and finesse.
Our media group as on top of Central Otago's Pisa Range ready for a Southern Hemisphere Proving Ground experience a few minutes after sunrise to make the most of the conditions while 2degC temperatures prevailed.
After a briefing to talk through the Mazda philosophy of vehicle dynamics and the workings of its i-Activ AWD and G-Vectoring Control systems it was onto the ice and snow.
GVC is a subtle but effective system that provides a small reduction in engine torque as a split-second response to steering inputs. It creates a very small shift in forward weight distribution that loads the outside front tyre, increasing grip and providing enhanced steering response. The snow is the ideal place to get a feel for GVC as it's of greatest benefit on low grip surfaces.
Mazda has also worked to blend fuel efficiency with rapid response from the i-Activ AWD system on its CX-5, CX-8 and CX-9 models.
Described as an on-demand predictive system - rather than being full-time or ondemand reactive - it reduces fuel consumption by keeping rear torque distribution as low as 1 per cent on high grip surfaces.
All the time it's crunching data from 27 sensors and making 200 calculations per second to control how much torque is sent rearwards via the electro-magnetic clutch of the Active Torque Transfer Coupling.
Information about vehicle and individual wheel speed, throttle position, steering input, brake pressure, gradient, outside temperature and even windscreen wiper position all influence how much torque gets sent to the rear wheels.
Its response is demonstrated by efficient launch acceleration from standstill on snow with no sense of delay between the front wheels beginning to slip and drive being directed to the rear wheels. With relatively late intervention from the stability and traction control electronics the CX cars accept throttle and can accelerate hard with some wheelspin on snow and some tail-out attitude is permitted sliding through a snow slalom.
The delayed electronic interventions a little later than many brands - is part of the Mazda philosophy of creating connection between driver and machine to deliver a driveable vehicle with some emphasis on fun. You could push the CX cars to some interesting angles in the snow slalom before the electronics started to lend a helping hand.
While the test sites offered a feel for the vehicle systems at work so to did the SHPG link road network. On gravel with a full snow covering the grip levels and steering bite offered confidence while concentrating hard to pick out the white road from the surrounding snow banks in misty visibility that dropped to 20 metres at times.
Undoubtedly a significant part of the assurance which the Mazdas showed on the South Island snow came down to tyre choice. My years in rally cars have been a good education in just how much the right tyres for the right conditions can make a huge difference.
Mazda had fitted all cars on the programme with Bridgestone's highly regarded Blizzak tyres. They are a nonstudded winter tyre with sharp edged blocks, a deep tread pattern and narrow sipes to achieve steering and braking bite along with forward traction in challenging winter conditions.
The combination of the right tyres for the frozen surfaces and Mazda's intelligent vehicle dynamics controls give the CX models a sure-footed stance and fun-todrive dynamics.
The thought crossed my mind that not many years ago winter tyres would have the predominant form of assistance to a driver on snow and ice surfaces with early anti-lock braking systems and traction control as much a hindrance as a help.
The millisecond electronic responses of modern cars offers a another layer of support to bite offered by winter tyres and it's nice to be reminded, that at least in part, some of that testing and development work is performed right here in New Zealand.
As the temperatures climbed a couple of degrees Mazda's SHPG experience meant soggy toes to accompany my frozen nose but it was a small price to pay for the most enjoyable day behind the wheel I've spent had for a some time.
GVC IS A SUBTLE BUT EFFECTIVE SYSTEM THAT PROVIDES A SMALL REDUCTION IN ENGINE TORQUE AS A SPLIT-SECOND RESPONSE TO STEERING INPUTS.